You’ve seen the iconic image of a runner bent over and touching his toes. You’ve probably seen plenty of runners doing this before races. So it may surprise you to hear that this so-called static stretching—attempting to lengthen muscles and tendons to increase flexibility—is generally not recommended.

Stretching has been hotly debated in recent years. There is no evidence that static stretching prevents injury or improves performance, experts now say. In fact there’s some evidence that it can hurt. When it comes to staying injury-free, functional range of motion is more important than flexibility.

“If you can run comfortably, and without injury, there is no need to stretch,” says William O. Roberts, professor in the Department of Family Medicine and Community Health at the University of Minnesota Medical School. He’s also RunnersWorld.com's “Ask the Sports Doc” columnist. (Read more about what he thinks about stretching here.)

Before your workout, your time is better spent warming up with dynamic stretching.

These moves, which include butt kicks and walking with high knees, improve range of motion and loosen up muscles that you’re going to use on the road. They also increase heart rate, body temperature, and bloodflow so you feel warmed up sooner and run more efficiently. Here's a video of a good dynamic warmup routine to try before your run:

Dynamic Warmup for Runners

This routine is designed to warm up the specific muscles used for running. Perform the moves before your run to loosen up muscles, improve range of motion, and increase your circulation.

After your run, if you have an area that still feels tight—the calves, hamstrings, hip flexors, IT bands, and quads tend to be tight after running—a little stretching may be in order. But it is not necessary. You might try a standing quad stretch, stand on one leg, bend opposite knee raise lower leg and hold it around the ankle. Check out some of the five 30-second stretches in this article.

The stretch should give you the feeling of slight discomfort in the muscle, however, do not stretch to the point that you feel a sensation that is sharp or intense. If you do, be sure to back off.